Fifth-generation (5G) wireless communication systems have been widely regarded as the next wireless communication standard beyond the current fourth-generation (4G) communication standard such as long-term evolution (LTE). The 5G wireless communication systems are expected to provide significantly higher data rate, improved coverage range, enhanced signaling efficiency, and reduced latency compared to the 4G wireless communication systems. The 5G communication systems are designed to operate based on extremely high frequency spectrum, such as millimeter wave spectrum ranging from 30 GHz to 300 GHz.
To help provide higher spectral efficiency, the 5G wireless communication systems are configured to support wider spectrum bandwidth with relatively narrower guard band. As such, a high-performance radio frequency (RF) filter(s) is necessitated in the 5G wireless communication systems to satisfy such industry and/or regulatory requirements as occupied bandwidth, out of band emission, and spurious emission. The RF filter(s) is configured to pass RF signals within a specified spectrum bandwidth, while suppressing RF signals outside the specified spectrum bandwidth, based on an oscillation (resonance) frequency generated by an internal or an external inductor-capacitor (LC) circuit. In this regard, the efficiency and quality of the RF filter(s) largely depends on accuracy of the oscillation frequency generated by the LC circuit. The accuracy of the oscillation frequency is often measured by a quality factor (Q-factor) of the LC circuit.
As the name suggests, the LC circuit typically includes an inductor(s) and a capacitor(s). The most common type of inductor(s) employed in a conventional LC circuit is a planar inductor(s). Given that the planar inductor(s) typically corresponds to a relatively low Q-factor, performance of the RF filter(s) may be degraded as a result. As such, it may be desired to improve the Q-factor of the conventional LC circuit(s) to enable a higher efficiency RF filter(s) for achieving desired spectral efficiency in the 5G wireless communication systems.